“It was the biggest gamble of my life,” the opera star Regina Resnik told The New York Times in 1967. “There were many opinions.” Resnik was speaking of her mid-career decision to switch from soprano to mezzo-soprano. Born in the Bronx, in 1922, the singer made her popular debut as a last minute replacement at the Metropolitan Opera in the mid–1940s. Her reputation as a soprano grew for 10 years. Then came the leap—and her success continued. Before Resnik died, in 2013, she performed leads in six languages at houses including the Vienna State Opera, La Scala, the Paris Opera, and her hometown Met. In honor of her centenary last year, the New York Public Library is exhibiting archival material that highlights Resnik’s “grace, versatility, and commitment to the city.” —Jack Sullivan